The user can disable replies to your Google+ posts and Youtube comments in your Google+ settings. The only tricky step is to make sure that you are updating the settings for Google+ profile or page connected to the channel that’s doing the commenting.
Steps to follow:
This functionality can be performed by the following steps;
Sign in to youtube channel:
Always sign in with the channel identity that you use to post comments. You can switch channel identities by clicking your avatar in the upper right corner and selecting a different channel.
Open the page connected to channel:
Click on the avatar in the upper right corner, then click your avatar a second time. That will open your channels profile page with you are acting as a manager.
Go to settings:
On Google+ click the Settings gear icon on the left menu. Under “Who can interact with you and your public posts” Change the settings for who can comment on your public posts?”
The user needs to change the settings so that only her circles or specific individuals can reply to your comments.
Always remember this feature is not available on smartphones.